There are numerous reasons you could be experiencing bleeding after sexual intercourse (also known as post-coital bleeding), and determining the cause is key in preventing it from happening again. If the problem is medical, you may need to have treatment before you can have sex without bleeding. The main medical causes for bleeding after sex are infections, cervical conditions like polyps or dysplasia and uterine conditions like endometritis, polyps and fibroids. It's important to get post-coital bleeding checked out by a doctor, as some of these conditions can have potentially serious affects of fertility. Minor surgery may be required to treat some of these conditions. Infections such as the common yeast infection can be cleared up with simple over-the-counter creams and medications, however.